Mathematics · Limits, Continuity and Differentiability

JEE Main 2026 — 8 April, Evening Shift — Question 36

Let f(x)={13,x≤π/2b(1−sin⁡x)(π−2x)2,x>π/2f(x)=\left\{\begin{array}{lll}\frac{1}{3} & , & x \leq \pi / 2\\ \frac{b(1-\sin x)}{(\pi-2 x)^{2}} & , & x>\pi / 2\end{array}\right., If ff is continuous at x=π/2\mathrm{x}=\pi / 2, then the value of ∫03 b−6∣x2+2x−3∣dx\int_{0}^{3 \mathrm{~b}-6}\left|\mathrm{x}^{2}+2 \mathrm{x}-3\right| \mathrm{dx} is :

  1. Option A:

    55

  2. Option B:

    22

  3. Option C:

    33

  4. Option D:

    44

    Correct

Answer: D

Step-by-step solution

lim⁡x→π2b(1−cos⁡(π2−x))4(π2−x)2=13⇒b=83\lim _{x \rightarrow \frac{\pi}{2}} \frac{b\left(1-\cos \left(\frac{\pi}{2}-x\right)\right)}{4\left(\frac{\pi}{2}-x\right)^{2}}=\frac{1}{3} \Rightarrow b=\frac{8}{3} ∫02∣x2+2x−3∣dx=∫02∣(x+3)(x−1)∣dx\int_{0}^{2}\left|\mathrm{x}^{2}+2 \mathrm{x}-3\right| \mathrm{dx}=\int_{0}^{2}|(\mathrm{x}+3)(\mathrm{x}-1)| \mathrm{dx} put x−1=t\mathrm{x}-1=\mathrm{t} ∫−11∣(t+4)t∣dt=∫−10(−t2−4t)dt+∫01(t2+4t)dt\int_{-1}^{1}|(\mathrm{t}+4) \mathrm{t}| \mathrm{dt}=\int_{-1}^{0}\left(-\mathrm{t}^{2}-4 \mathrm{t}\right) \mathrm{dt}+\int_{0}^{1}\left(\mathrm{t}^{2}+4 \mathrm{t}\right) \mathrm{dt} (−t33−2t2)−10+(t33+2t2)01=4\left(\frac{-t^{3}}{3}-2 t^{2}\right)_{-1}^{0}+\left(\frac{t^{3}}{3}+2 t^{2}\right)_{0}^{1}=4

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Mathematics
Chapter
Limits, Continuity and Differentiability
Topic
Continuity